1 files changed, 95 insertions, 0 deletions
diff --git a/packages/gtk2/examples/helloworld/helloworld.pas b/packages/gtk2/examples/helloworld/helloworld.pas
new file mode 100644
index 0000000000..b929707fa1
--- /dev/null
+++ b/packages/gtk2/examples/helloworld/helloworld.pas
@@ -0,0 +1,95 @@
+program HelloWorld;
+
+{$mode objfpc}{$H+}
+
+uses
+  Glib2, Gdk2, Gtk2;
+
+(* This is a callback function. The data arguments are ignored
+ * in this example. More on callbacks below. *)
+procedure hello(Widget: PGtkWidget; Data: gpointer); cdecl;
+begin
+   g_print ('Hello World'#13#10);
+end;
+
+function delete_event( Widget: PGtkWidget; Event: PGdkEvent; Data: gpointer):gint; cdecl;
+begin
+  (* If you return FALSE in the "delete_event" signal handler,
+   * GTK will emit the "destroy" signal. Returning TRUE means
+   * you don't want the window to be destroyed.
+   * This is useful for popping up 'are you sure you want to quit?'
+   * type dialogs. *)
+
+  g_print ('delete event occurred'#13#10);
+
+  (* Change TRUE to FALSE and the main window will be destroyed with
+   * a "delete_event". *)
+
+  Result:=gTRUE;
+end;
+
+(* Another callback *)
+procedure destroy(Widget: PGtkWidget; Data: gpointer); cdecl;
+begin
+  gtk_main_quit;
+end;
+
+var
+  (* GtkWidget is the storage type for widgets *)
+  Window: PGtkWidget;
+  Button: PGtkWidget;
+begin
+
+  (* This is called in all GTK applications. Arguments are parsed
+   * from the command line and are returned to the application. *)
+  gtk_init (@argc, @argv);
+
+  (* create a new window *)
+  window := gtk_window_new (GTK_WINDOW_TOPLEVEL);
+
+  (* When the window is given the "delete_event" signal (this is given
+   * by the window manager, usually by the "close" option, or on the
+   * titlebar), we ask it to call the delete_event () function
+   * as defined above. The data passed to the callback
+   * function is NULL and is ignored in the callback function. *)
+  g_signal_connect (G_OBJECT (window), 'delete_event',
+                      G_CALLBACK (@delete_event), NULL);
+
+  (* Here we connect the "destroy" event to a signal handler.
+   * This event occurs when we call gtk_widget_destroy() on the window,
+   * or if we return FALSE in the "delete_event" callback. *)
+  g_signal_connect (G_OBJECT (window), 'destroy',
+                      G_CALLBACK (@destroy), NULL);
+
+  (* Sets the border width of the window. *)
+  gtk_container_set_border_width (GTK_CONTAINER (window), 10);
+
+  (* Creates a new button with the label "Hello World". *)
+  button := gtk_button_new_with_label ('Hello World');
+
+  (* When the button receives the "clicked" signal, it will call the
+   * function hello() passing it NULL as its argument.  The hello()
+   * function is defined above. *)
+  g_signal_connect (G_OBJECT (button), 'clicked',
+                      G_CALLBACK (@hello), NULL);
+
+  (* This will cause the window to be destroyed by calling
+   * gtk_widget_destroy(window) when "clicked".  Again, the destroy
+   * signal could come from here, or the window manager. *)
+  g_signal_connect_swapped (G_OBJECT (button), 'clicked',
+                              G_CALLBACK (@gtk_widget_destroy), window);
+
+  (* This packs the button into the window (a gtk container). *)
+  gtk_container_add (GTK_CONTAINER (window), button);
+
+  (* The final step is to display this newly created widget. *)
+  gtk_widget_show (button);
+
+  (* and the window *)
+  gtk_widget_show (window);
+
+  (* All GTK applications must have a gtk_main(). Control ends here
+   * and waits for an event to occur (like a key press or
+   * mouse event). *)
+  gtk_main ();
+end.